<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title></title>
    <script>
         let n = 60
         window.onload = function(){
            setInterval(cutdown,1000)
            function cutdown(){
               if(n>0){
                  n--
                  document.getElementById('weo').innerHTML = n
               }
            }
         }
     </script>
  </head>
  <body>
     
     <div id="weo">60</div>
  </body>
  </html>